DE2715499A1 - METHOD AND DEVICE FOR USE OF ENERGY FROM UNDERGROUND GEOTHERMAL SOURCES - Google Patents

Description

Patent attorneys Dipl. - 1ng. C u rt Wallach

Dipl.-Ing. Günther Koch

β Dipl.-Phys. Dr Tino Haibach

Dipl.-Ing. Rainer Feldkamp

D-8000 Munich 2 · Kaufingerstraße 8 · Telephone (0 89) 24 02 75 ■ Telex 5 29 513 wakai d

Date: April 6, 1977

Our reference: 15 827 -

Designation: Process and device for

Use of energy from underground geothermal sources

Applicant: Sperry Rand Corporation

1290 Avenue of the Americas
New York, NY IOOI9 / USA

Representative: Dipl.-Ing. C. Wallach

Dipl.-Ing. G. Koch
Dr. Tino Haibach
Dipl.-Ing. R. Feldkamp
8OOO Munich

Inventor: Hugh Brookie Matthews

410 Edgebrook Road
Boylston, Massachusetts / USA

09842 / 09U

The invention relates to a method and a device for using energy from underground geothermal energy Sources, for example from hot brine deep wells »

In German Offenlegungsschrift 2,419,237 and US patent specification 3,898,020 describes methods and apparatus that represent a significant advance in the art the extraction of geothermal power arise because it does not rely on the use of the rare dry one Steam-producing geothermal sources are limited and because these methods and devices still do not have any Problems with the separation of steam and geothermal brine and the resulting corrosion arise, as they occur in known systems using wells that contain a mixture of steam and hot water deliver. The German laid-open specification and the US patent describe an arrangement which is described below in more detail with reference to Figures 1 and 3a and 3b of the drawings is explained.

An improvement to this basic arrangement is described in German Offenlegungsschrift 2,530,635. All three mentioned patents or laid-open documents describe geothermal energy generation systems, the thermal Exploiting energy stored in underground heat sources in the form of hot solvent leading well water is to extract superheated steam from a flow of clean water introduced from the surface. The superheated steam is then used to drive a turbine-powered pump in the well for pumping the hot brine with high pressure and always in a liquid state down to the surface of the earth, where this brine or the Solvent-carrying well water uses its energy in a binary, closed-circuit heat exchanger-steam turbine-alternator combination to produce

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supply of electrical power. The rest of the brine is pumped back into the earth while the clean, cooled water is recovered in the surface-mounted system and is returned to the deep well pumping system to generate steam and also to lubricate the fluid bearings that power the turbine powered pumping system to store. The German Offenlegungsschrift 2 530 635 describes a similar system with improvements in the shape of the hydrodynamic radial and thrust bearings as well as in of hydraulic fluid bearing lubrication systems. Farther is composed of a compact deep well steam turbine engine with features of the surface-mounted control and power generation systems.

The invention is based on the object of the known geothemical To improve energy recovery systems so that the manufacturing and operating costs of the device are substantial can be reduced, with certain elements arranged on the surface and in the deep well being omitted can, so that an apparatus with reduced complexity and significantly increased efficiency results.

Based on a method of the type mentioned at the beginning, this object is achieved according to the invention by the following steps solved: transferring a first liquid, which is initially in a relatively cool state, from a first station near the earth's surface to a second station in the earth, using the thermal energy for Conversion of the first liquid into the supercritical state during the transfer from the first station to the second station, use of the first liquid in the supercritical state to drive pumping devices at the second station, using the pumping means to pump a second liquid from the im Inward of the earth lying hot area to the first station below

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a pressure at which the second liquid is always kept in the liquid state, converting the into supercritical State of the first liquid after the drive of the pump devices in a thermally isolated relationship the second liquid to the first station, and taking the thermal energy from the supercritical state first liquid at the first station to generate useful power.

Furthermore, based on a device of the type mentioned at the outset, this object is achieved according to the invention in that that the device comprises the following parts: heat exchanger devices, which are essentially from a first station adjacent to the earth's surface to a second station in the interior of the earth, to a first initially in relative transfer cool liquid from the first station to the second station, while the first liquid is transferred into the supercritical state for driving drive devices at the second station, from the Drive means driven pumping means at the second station for pumping a second liquid from the hot area in the earth's interior under a pressure at which the second liquid is always kept in a liquid state becomes, in heat exchange relationship with the heat exchanger facilities standing line parts for transferring the second liquid from the pumping device to the first station, thermally insulating line parts for transferring the first liquid in a supercritical state from the drive devices to the first station in a thermally isolated relationship with respect to the second liquid, and thermal energy transfer means at the first station for extracting a portion of the thermal Energy from the first liquid, which is in a supercritical state, to generate useful power.

709842/0914

Further advantageous refinements and developments of the invention emerge from the subclaims.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawing.

Show in the line:

Fig. 1 is a side view, shown mainly in cross-section, of a known geothermal Deep well energy recovery device with the interacting surface control and power generation devices in a schematic Shape;

FIG. 2 is a view similar to FIG. 1 of an embodiment of the gpothermal according to the invention Energy recovery device;

J5a to 5b are graphic representations for explaining the

Mode of operation of the devices according to FIGS. 1 and 2;

6 to 9 are cross-sectional views along the embodiment of the device according to FIG. 2 at different heights, showing tapering heat exchanger elements of the device;

10 shows a wing design of a heat exchanger element

for use in the device according to Figures 6 to 9;

11 is a cross-sectional view of a further embodiment

management form of a tapered heat exchanger element;

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Fig. 12 is a partially sectioned view a further embodiment of the device;

13 is a partially shown in cross section

View of part of the heat exchanger device according to FIG. 12;

Figure 14 is a cross-section of part of the device

according to Fig. 2;

15 shows a plan view of a turbine wheel of the device according to Fig. 14;

Figure 16 is a fragmentary view taken along the line

I6-I6 of Figure 15;

17 shows a developed representation of a part

the turbine device according to FIG. 14;

Fig. 18 is a partially shown in cross section

View of a further part of the device according to FIG. 2.

Fig. 1 shows the general structure and properties the device as described in the above-mentioned German Offenlegungsschrift 2,419,257 and the US patent 3 898 020 is shown and described. This device includes a surface energy conversion system and a co-operating geothermal energy extraction system that is placed in a deep well is immersed, which extends in layers far below the earth's surface, with this energy dissipation system located at such a depth that an abundant supply of extremely hot water under high pressure is reliable is available. The deep well device closes

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an active pumping arrangement, which in a commonly used Well lining 5I is arranged. The device 1 includes a well head section 49 one that is partially above the surface of the earth 50 and extends downwards. At or above the subterranean halo Source of hot pressurized water are available extensions of the well pipes with a regulator and Steam generator input section 75 in connection. A steam generator section 76, a steam turbine engine section 77 » a rotary support bearing section 78 and a hot water pumping section 79 follow in close succession in increasing depth. The well lining 5I extends from the surface of the earth 50 downward and generally concentrically surrounds an inwardmost steel tube 53 'one inner conduit for supplying a flow (in the direction of arrow 56) of relatively cold clean water to the ground of the fountain. A second stronger tube 52 surrounds the pipe 53 and forms an annular conduit 55, extending from the well head section 49 to the turbine engine section 77 extends so that the turbine exhaust steam can flow in the direction of the arrow 57 to the earth's surface 50, from where from which steam flows through an extension pipe 24 into a condenser 23. The condensed steam is then with With the help of a conventional pump 21 arranged on the surface via a pipe 22 and is pumped via the in the Center arranged inner tube 53 passed back into the well.

It can be seen from Fig. 1 that the relatively clean cool water through the inner tube 53 down into the area of a Manifold 70 is pumped. At the pipe branch 70, the water flowing down is on two branch lines divided up. As described in the above-mentioned patents or laid-open publications, the first branch line conducts clean lubricating water through a pipe 71 for lubrication of a storage system in the storage system section 78. The second branch conduit directs some of the clean water over one

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Pressure regulator 72 and via a distribution pipe 73 to an inlet manifold 74 of a steam generator 80, which is formed as an annular chamber between the pipe 52 and a pipe 59. Accordingly standing steam is generated under high pressure and used to drive a steam turbine engine, which is located within the steam turbine motor section 77th The task of the turbine motor located on section 77 and mounted in rotary bearings arranged in bearing section 78 is to drive a hot water pump which is arranged at section 79. Hot, high pressure water is driven upwardly by rotating pump vanes 81 between a rotating conical end 82 of the pump shaft and an associated pump shell. The hot geothermal water is pumped in the direction of arrow 58 at a high speed in the annular conduit 54 between the tube 52 and the well casing 51 upward, so that the geothermal energy contained in the water can be utilized at the surface. The hot water is usually pumped up to the earth's surface 50 in the form of a brine or solvent-containing liquid, this hot water being kept at all times under a pressure which prevents vapor formation so that dissolved salts are prevented from separating out at any point of possible vapor formation will. As the well water is pumped up, heat is transferred from the well water through the walls of the pipe 52 on the steam generator 80 to form a high energy dry steam.

The hot geothermal water pumped up to the earth's surface in line 54 is passed through a pipe I9 into a heat input element 16 of a conventional heat exchanger 15 in order to dissipate heat from the water with the aid of an organic liquid which flows in the conventional heat exchanger output element 14 cooperating therewith . The cooled geothermal water is pumped along with the lustful salts with the aid of a pump 17 through a pipe 20 and into

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a return well lining 18 was initiated to return the water to a point well below the surface of the earth. The return well formed by the well lining 18 may be located at a location remote from the geothermal well of the well lining 5I, but is preferably arranged to allow the returned water to flow through permeable layers of earth towards the geothermal heat source which exploits the geothermlsche wells, as is indicated by the arrows 84th

The binary surface-mounted energy conversion system removes the energy from the heat exchanger 15 to drive the conventional surface-mounted steam turbine engine. For this purpose, a conventional organic liquid, which enables improved Rankine cycle operation, can be passed via a pump 12 and a pipe 13 to the heat exchanger element 14, in which it is converted into high-energy vapor, which via a pipe 14 of the input stage of a conventional multi-stage turbine engine 1 is supplied. After the generation of useful power, the turbine exhaust steam flows via a pipe 5 through an input element 10 of a condenser 9 and then flows as a condensed liquid through a pipe 11 to the pump 12 before this liquid enters the heat exchanger 15. The condenser 9 can be cooled by means of a cooling water flow from a cooling tower (not shown) through a pipe 6, a heat exchanger element 8 and a pipe 7. Thus, the combination uses an energy that is in a geothermal deep well disposal, in order to generate electric power with high efficiency at the terminals 3 of a conventional alternator 2 which is driven by the steam turbine operated with organic motor. 1

The known device shown in Fig. 1 has three operating circuits, namely:

709842/0914

COPY

1. A geothermal brine circuit that runs the pipe 54, the heat exchanger element 16, the pump 17, the return well 18 and the permeable layers (Arrows 84) that connect the well bottoms together.

2. A binary fluid primary energy conversion circuit with the heat exchanger element 14, the turbine engine 1, the condenser element 10, the pump 12 and the pipe 13, and

3. a drive circuit for the pump located at the lower end of the well with the flow of clean Water through the pipe 53. the regulator 72, the steam generator 80, the steam turbine engine in the section the line 55 »the pipe 24, the condenser 23, the Pump 21 and pipe 22.

In the brine circuit the geothermally heated brine in operation usually occurs in the well below the pump section 79 at a location, for example I83O m among the Earth's surface at a typical temperature of 150 ⁰ C and a pressure which is high enough that, even at a depth of 300 m or less below the surface of the earth 50, the pressure is still sufficiently above the saturation pressure of the brine, so that cavitation and the formation of steam on the pump blades 8l are prevented. The deep well pump at section 79 provides sufficient additional pressure (e.g. 1.4 kp / m / 200 psi) to raise the geothermal well brine above the earth's surface 50, while still maintaining sufficient pressure above saturation pressure to cause steam formation and cavitation the way to the additional return pump I7. On this line section, the geothermal brine transfers sufficient heat to the steam generator 80 in the drive circuit to drive the turbine engine in section 77.

COPY

ORIGINAL INSPECTED

The geothermal brine then reaches the primary heat exchanger 15 with a temperature of for example 138 ⁰ C. The auxiliary pump 17 of the geothermal brine leads have enough power to make them move out of the heat exchange element 16 with a temperature of for example 54.5 ⁰ C and removed in the to pump arranged return line well, which is formed by the well lining l8, namely both

for example at a pressure of 17.6 kp / cm. As mentioned earlier, the return well comes in handy with that The bottom of the geothermal well is connected by water-permeable layers so that the brine is heated again and can be continuously circulated.

The binary primary conversion cycle can be carried out by the usual supercritical organic Rankine cycle ABCDA according to Fig. 3a, this figure being a diagram shows, which shows the pressure P versus the enthalpy h. In this diagram, the one delimited by curve 142 is defined Area l4l the two-phase area of the organic liquid and the organic working liquid remains essentially outside and away from this two-phase region 14l, so that it covers most of the cycle is in a supercritical state. Figures 3a and 3b are in connection with the operation of the known System of Fig. 1 explained. 3b shows curves of the respective temperature within the brine liquid or the organic liquid as it passes through the heat exchanger 15 in the countercurrent direction. The dashed vertical Line 146 represents the position of the inlet for the organic material and the outlet of the brine, while the dashed line vertical line 147 the location of the exit of the organic Material and the entrance of the brine to the heat exchanger 15 represents. The horizontal coordinate of Figure 3b therefore represents the path or the route along the heat exchanger.

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The segment AB according to FIGS. 3a and 3b represents an increase in pressure with relatively small but mutually corresponding enthalpy and temperature changes; the effect is that of the feed pump 12, which provides sufficient additional pressure that the organic liquid remains well above the two-phase region 141 when heat is transferred to the organic liquid along the path BC. There is a considerable loss of energy due to the nature of the feed pump 12. If only a slight pressure drop occurs, the path BC represents the passage of the organic liquid through the heat exchanger element 14 with certain flow losses. The enthalpy and the temperature are increased considerably.

The path CD represents the relaxation or expansion of the organic vapor in the turbine engine 1. A considerable enthalpy is released during the corresponding pressure drop to point D, which point is desirably close to the two-phase limit of curve 142 . When the point D is located within the curve 142, results in a certain droplet erosion and a loss of energy and if this point D is located too far outside, the efficiency is reduced unnecessarily. The cycle is closed by the path DA, which corresponds to the effect of the capacitor 9 when the enthalpy h is lowered back to the initial value along a path with essentially constant pressure within the two-phase region 141. Overall it can be seen that the thermodynamic processes are as follows:

(A - B) Feed pump operation

(B - C) Heat transfer from the brine to the organic one

Workload, (C-D) Relaxation and expansion of the organic

Working fluid in the turbine,

(D - A) condensation of the organic liquid, and (G - H) heat dissipation from the brine along a curve,

a linear or other function of the path

can be.

709842 / 09U ./.

For a typical but exemplary sentence of operating conditions, taking into account losses can see the pressures and temperatures at the different alphabetical Points according to Figures 3a and 3b, the values according to of the following Table I:

pressure Table I. tempera door ° C P.S.I .A. ⁰ F 26.5 33 kp / cm 80 32.3 A. 930 2.32 90 165.0 E. 900 65.5 330 29.5 C. 38 63.3 85 175.0 D. 175 2.6? 350 52.5 G 150 12.3 127 H 10.5

The temperature difference ΔΤ (Η-Β) is 20.6 ⁰ C (37 ° F); ΔΤ (Η-Α) is 26.1 ⁰ C (47 ° F) and AT (GC) is 11.1 ° C (20 ⁰ F). The result is a mean effective temperature difference of Ii, 1 ° F. It can also be seen that in the device according to FIG. 1 the heat capacity of the working fluid or dQ / dt is a somewhat increasing function of the temperature of the working fluid. On the other hand, the effective heat capacity of the brine is characteristically almost constant over the entire operating temperature range in the device according to FIG. 1. These special thermal properties lead to design restrictions which lead to compromises in the design of the device according to FIG. in view of the well-known necking effect that occurs in many cases with heat exchangers. As will be explained in more detail, this constriction effect makes such heat exchangers ineffective when the temperature difference limited by the arrows 203 according to FIG. 3b becomes zero.

The embodiment of the device shown in FIG should also address the structural problem described above

709842/0914 ./.

remove. Fig. 2 shows a simplified surface energy conversion system, that with a less complicated and more efficient geothermal energy extraction system cooperates, the latter in turn being arranged in a deep well that extends in layers, which have an abundant influx of geothermally heated water or geothermally heated brine under relatively high Have pressure. The deep well device in turn includes an active brine pumping device located in a well lining 125 is below the depth at which vapor formation would occur. The arrangement according to FIG. 2 closes in turn a well head section 149, which is partially is above the earth's surface 13I and is from this extends downwards. Towards the geothermal spring, extensions of the well pipes stand directly with a liquid turbine engine section 170, a rotary support bearing portion 171 and a hot water pumping portion 172 in communication, the are arranged in close succession with increasing depths.

The well liner 125 extends from a surface cover or head plate 120 down, generally concentrically surrounding a relatively large tube 12j5 which is an annular Line 126 forms through which the hot geothermal brine, which is always in a liquid state, goes upwards can flow. Between the tube 123 and an inner tube 121 an annular conduit 124 is formed, which allows a downward flow of an organic liquid in supercritical condition allows to run the fluid turbine engine in the turbine section I70. After driving the turbine, the partially cooled down one Liquid in the supercritical state with no phase change returned upward in conduit 122 formed in tube 121.

An intense heat exchange is through the walls of the pipe between the upwardly flowing hot geothermal

709842/0914 ./.

Water and the working fluid flowing downwards, which is heated in the annular conduit 124 to a supercritical state. On the other hand, a Heat transfer between the heated working fluid in the annular conduit 124 and the liquid flowing upward in the inner conduit 122 is greatly reduced. For this purpose only a small part of the tube 121 is made of metal and most of the conduit 122 is formed by a tube made of thermally insulating material. Such an insulating tube is shown in Fig. 2 as pipe 127, which is connected to the metal well head inner pipe 121 in the usual way, for example by a threaded connection 128. The insulating tube 127 can be connected to a threaded connection in a similar manner 129 (Fig. 14) connected to a metal pipe (IjK) located in the fluid turbine engine section 170, which will be described later. The tube 127 can be formed in a conventional manner from refractory materials, which with a suitable binder, and it can contain glass, asbestos or similar fibers. Alternatively the pipe 127 can be a steel pipe with a layer of conventional powdered thermally insulating material, this in the usual way on one or both cylindrical Surfaces of this pipe is sprayed or connected to these in some other way. Reinforced plastic pipes are suitable at the lower end of the operating temperature range.

When the pump is operating in the pump section 172, the geothermal fluid in line 126 always in a fluid state by the action of pump blades 174 upward driven, these pump blades via a shaft 173 of the fluid turbine motor of section I70 will. During the rise of the geothermal fluid in line 126, there is an intense one Heat transfer through the walls of the tube 123 into the after

709842 / 09U

working fluid flowing down in line 124. The geothermal brine flows up and in line 126 via a branch outlet pipe 132 at the earth's surface 131 so that it is fed to a Rücklei processing well 133 in a considerably cooled form, which is similar to the well which was formed by the liner 18 of FIG. Accordingly, the energy dissipation cycle can be continuous be repeated.

The organic working fluid that has one on the surface arranged branch pipe 118 is introduced into the line 124, flows between the thermally conductive pipe 123 and the thermally insulating tube 127 with a considerable Volume down, so that the greater part of the geothermal energy was transferred to the working fluid, if this causes the turbine engine of section 10 to be in supercritical State reached. After supplying the energy to drive the turbine, the shaft I83 and the blades 174 of the Brine pump, the partially cooled working fluid flows in the supercritical state in the line 122 upwards without that there is a change of state and the working fluid then flows in the line in a supercritical state without change of state upwards and flows through the pipes II9 and 104, which are arranged in series one behind the other, to the entrance of a usual multi-stage steam turbine 301. In this way, will Energy supplied by the steam, which is calibrated at the Singang nozzles of the turbine 101 forms, around the alternating current generator arranged on the earth's surface or generally a generator 102 to drive the electrical power to the Output terminals 103 supplies.

The steam occurring at the output stage of the turbine 101 and flowing through the pipe 105 is caused by the effect of the capacitor element 110 of a capacitor 109 is reversed into a liquid. The cooling of the condenser 109 is by a flow of water, for example from a

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(not shown) cooling tower via a pipe 106, a condenser element 108 and achieved via a pipe 107 back to the tower. During normal operation, the organic working fluid flows through the tubes 111, 112, through an open valve 114 and via a T-connection II7 in the branch pipe II8 to again to be circulated. The valve Il4 is only closed under unusual circumstances, such as during start-up of the device and in this case the valve Ho is opened instead of the valve 114 and a pump II5 is in Operated to induce flow through pipe 113 »pump 115, valve 116 and T-junction II7, so that there is sufficient pressure to start the turbine engine of section 170, whereupon normal operation with valve 116 closed and valve 114 open.

In clear contrast to the device according to FIGS. 3 a and 3 b, the device according to FIG. 2 has only two Working groups, namely:

1. A geothermal brine circuit with the line 126, the pipe I32, the return fountain I33 and the permeable layer 84 connecting the bottom of the two wells, and

2. a completely separate cycle, which is referred to here as the organic cycle and the the flow of the organic liquid through the pipes 111, 112, II8, the well pipe 126, the Liquid turbine engine in section 170, line 122, pipes 119, 104, the steam turbine 101 and the heat exchanger 110 comprises.

During the operation of the brine tank, the brine solution is pumped up from the bottom of the well lining 123 with the help of the pump ata section 172 and it receives “Inen Zusatrdruok, thus

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it moves across the earth's surface 13I. In contrast to the device according to FIG. 1, the brine transfers essentially all of its available heat through the walls of the very long heat exchanger 123 into the organic liquid in the line 124 of the organic cycle. After driving the liquid turbine engine in the turbine section 170, the organic working fluid reaches the earth's surface 131 at a relatively reduced temperature, for example on the order of 49 ⁰ C to 65.5 ⁰ C when the brine in the well has a temperature of approximately 150 ° C usually as a function of the temperature of the final cooler. In contrast to the operation of the known device, in which the rising geothermal brine essentially maintains its initial temperature, the temperature of the brine in line 126 is continuously reduced as it rises and the pressure in the brine also falls continuously and accordingly it is not It is necessary that the pump of the section I72 located at the bottom of the well generates a considerable additional pressure in order to prevent steam formation and all the work produced by the pump located in the well serves only to overcome flow friction losses. Furthermore, the additional pump 17 according to FIG. 1 can be omitted, because, however, essentially the same Tlefbrunnen pump specifications are still used. Furthermore, there are no other manufacturing and operating costs; For example, the primary binary circuit heat exchanger 15 of the device according to FIG. 1 is omitted and its function is taken over by the relatively simple and more efficient heat exchanger, which is formed by the well lines 124, 126, which must be present in each case for the respective liquids to transport.

The operation of the supercritical organic cycle 2 can be explained in conjunction with the diagrams according to FIGS. 4a and 4b, it being understandable is that Fig. 4a is analogous to Fig. ^ a, while the

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FIG. 4b is analogous to FIG. 3b. The one in the supercritical state operated organic cycle is shown in Fig. 4a by the cycle ACFEDA. Starting at the exit of the Capacitor element UO, which corresponds to point A in FIG. 4a, the working fluid flows in line 124 between the heat exchanger tube 123 and the thermally insulating Outlet pipe 127 downwards. The pressure gradient caused by gravity in the increasing depth of the Liquid in line 124 increases continuously; the liquid temperature and enthalpy also increase continuously because the organic liquid heats from the geothermal brine during the entire passage through line 124 receives. The liquid in line 124 remains in the single phase supercritical state along curve 148 and normally just outside curve 142 which defines the two-phase region 141 of FIG. 4a and it reaches the turbine engine in section 170 with maximum temperature, with maximum pressure and with maximum heat content (enthalpy), as shown by point C. In practice it can be allowed that the curve 148 drops slightly into the two-phase region 141, as will be explained in more detail below. The shape of the curve 142 is naturally determined by the physical properties of the organic liquid or fixed while the shape of the curve 148 changes readily using the measures according to the invention can be. In general, the shape of curve 148 shown in FIG. 4a is adjusted and selected so that the introduction of heat in the organic liquid at constant pressure is avoided, as shown in Flg. J5a is the case.

Because the pressure and the temperature increase together along the path AC of Fig. 4a, the specific heat remains dQ / dT the supercritical fluid more closely approximated with the Temperature constant than in the circuit of Fig. 3b, at which the temperature was increased at substantially constant pressure. This property of a relatively constant spec-

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Thermal heat can be achieved with a wide range of organic liquids suitable for use in thermodynamic systems, including isobutane, propane, propylene, difluoromethane (CH ₂ F ₂ ), and others commonly used high molecular weight Coolants based on carbon hydrogen or chlorofluorocarbon halogen, for example CClF ₂ -CClF ₂ , CC1, F or CClF ₂ -CF ₅ .

The basic properties that the organic liquid must have in the device according to the invention is that their specific heat properties are essentially adapted to the substantially constant specific heat properties of the geothermal brine solution should. If this requirement is met by the selected organic liquid, it is possible to produce an ideal, small, substantially constant temperature difference between the rising brine solution in line 126 and that after Organic working fluid flowing below in line 124 over the entire length of heat exchanger tube 123 to achieve. With the arrangement according to the invention, a higher maximum temperature of the organic liquid as it enters the turbine engine section 170 without the above-mentioned disadvantages that are inherent in the brine circulation pump and the heat exchanger device no longer required in the device of FIG. 1, occur. Furthermore, a considerably larger amount of heat can be used taken from the brine so that it is brewed at a lower temperature. Hence the danger of the effect of embedding is substantially reduced, if not even completely eliminated.

The supercritical fluid then expands as it passes through the turbine hub 170, with a loses a small amount of pressure and 4 enthalpy when traversing the path CF. There is no phase change

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on traversing the path CF, so that the liquid in the supercritical state then flows upwards within the insulating tube 127 at a substantially constant high temperature, with little expansion occurring. On the corresponding path FE according to FIG. 4a, small flow losses can occur in the liquid. When the earth's surface I31 is reached, the liquid emerges from the power turbine 101 as a gas, releasing the remaining major part of the thermal energy available in this liquid. The corresponding ED path is a path of constant entropy apart from losses, in particular on the blades of the turbine 101, by the direction of a certain deviation of path ED may be caused. The path ED of Fig. 4a (and also the path CD of Fig. 3a) may to some extent be outside or inside the two-phase region 141 , contrary to what is shown, if so desired. The cycle is finally completed along the path DA with constant pressure due to the operation of the capacitor I09, and the cycle is then repeated.

In the device according to FIG. 2, the pump 12 according to FIG. 1 is not required in order to produce the pressure difference between points A and C according to FIG. 3a. The desired pressure difference results partly from the temperature and thus the density of the organic liquid in the line 124 and therefore from the increased pressure drop of the organic liquid column which is arranged between the heat exchanger tube 123 and the insulating outlet tube 127. The expanding column of organic liquid in line 122 causes a reduced density so that a pressure differential is established which causes the organic liquid to circulate through turbine section 170 in the direction of arrows 134, 135 of FIG. A very large amount of energy is available when the flow friction

./. • 7 09842/0914

Losses can be reduced as much as possible through the use of relatively large-volume lines. Even if the required well lining 125 may be larger than that used in conventional oil wells the corresponding additional costs for the larger diameter well and the corresponding one Larger diameter pipes at a depth of 600 m, for example, are significantly lower than the cost savings, resulting from the elimination of the binary circuit feed pump 12 and the primary heat exchanger 15, the drive circuit condenser 2] 5 and the pump 21 and the brine circuit auxiliary pump 17 of Fig. 1 results. Furthermore, the value of the electrical power is that for a given brine source temperature and flow velocity is generated, in the embodiment according to FIG. 2 is substantially greater.

Overall it can be seen that the thermodynamic cycle of the device according to FIG. 2, its properties are shown in Figures 4a and 4b, proceeds as follows:

(A - C) heat transfer to the organic working fluid,

(C— F) Pumping the brine

(F - E) work done in lifting the organic liquid to the surface of the earth,

(E - D) expansion of the organic liquid in the main turbine,

(D - A) condensation of the organic liquid, (0 - H) heat removal from the brine and transfer

this heat on the organic working fluid,

(I - J) Recovery of work done in lifting (F - E) as heat.

For a typical. However, only an exemplary sentence of operating conditions corresponding to those in Table I,

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however, for the device according to Flg. 2 are the pressures and temperatures at the various alphabetical Points of Figures 4a and 4b indicated in the following Table II:

Table II kp / cm " tempera ⁰ F door pressure 2.32 80 ° C P.S.I .A. 63.3 333.5 26.5 33 49.6 321 167.5 900 19.35 240 160 705 2.67 85 115 275 64.0 351.5 29.5 38 177.5 910

A.
C.
F.
E.
D.

+ Return pressure

H return pressure 100 37.8

The temperature difference Z ^ T (GC) is 10 ⁰ C; ΛΤ (Η-Α) is 11.1 ° C and the mean effective temperature difference is 11.1 ° C, but the risk of the occurrence of the constriction effect is advantageously eliminated. It can be seen that the heat capacity, which is constant with the temperature, makes the occurrence of the constriction effect impossible, whereby AT (GC) and ΔΤ (Η-Α) are always positive and finite.

In the ideal case, there is a finite, generally constant temperature difference over the entire length of the pipe 123 2 between the geothermal brine and the organic working fluid. The use of an exemplary embodiment The present invention desirably acts to bend down the curve of the organic Working fluid away from the brine curve, so that a desired but small, relatively constant differential temperature difference is easily achieved. The work flow conditions are therefore selected so that the

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two curves do not touch on EinschnUrungspunkt, ie at the point of their smallest distance shown by the arrows 205 in FIG. yo. Preferably the two curves are at least substantially parallel as in FIG Working fluids are desirable. In practice, an approximate adjustment of the specific heat value is acceptable (with a reduced efficiency, however) as long as the curves do not touch, because in this case the heat exchange is completely stopped. In the device according to FIG. 1 there is the risk of an undesirable occurrence of the constriction effect, which causes a difficult structural selection and forces a compromise between the size of the heat exchanger 15 and a reduction in the maximum temperature of the organic working fluid and a higher brine return temperature, so that there is a reduced energy transfer to the organic liquid and a lower conversion efficiency. These problems and the efficiency and cost problems resulting therefrom are essentially eliminated by the device according to the invention.

The device according to FIG. 2 is very versatile and it can be seen that it can be operated successfully in additional operating modes, as will be described in more detail with reference to FIGS. 5a and 5b. For example, in a further usable operating mode, the arrangement has the effect that the organic working fluid has a heat capacity which practically has a slightly negative thermal coefficient, as will now be explained in more detail. This mode is obtained by using the diagram of Fig. 5a, where the line 143 slightly NaOH down into the loading reioh is printed 141 duroh the curve bounded 142nd The thermodynamic cycle processes are otherwise

* ■ <. ? ι oil f

generally the same as explained with reference to the operating mode according to FIGS. 4a and 4b. Again is merely the heat exchange between those flowing in countercurrent Consider liquids.

Examination of the graphs shows that if the temperature difference is high at the hot end 147 of the heat exchanger, (at the end at which the brine enters and the organic working liquid exits) the organic liquid finally does not reach the highest possible temperature, so that the efficiency of the cycle is therefore reduced. A high temperature difference at the cold end 146 results in a higher temperature of the outflowing brine, so that a smaller amount of heat flows into the organic liquid. the However, heat transfer is proportional to the mean effective temperature difference through the heat exchanger walls and the greater this difference, the smaller the total heat exchanger surface that is required. It is therefore without further understandable that it is desirable to minimize the temperature differences at the ends 146, 147 of the To use heat exchanger, but that the highest possible temperature differences over the rest of the heat exchanger should occur.

In FIGS. 2b, 4b and 5b, arbitrary but typical operating conditions have been selected for comparison purposes so that the condenser outlet temperature at point A is always 26.5 ° C. Thus, in Fig. 3b, the temperature at the inlet end of the feed pump 21 according to Flg. 1 is 26.5 ⁰ C and in the figures 4b and 5b, the inlet pipe 118 for deep wells heat exchanger a temperature of 26.5 ° C. In the usual Rankine cycle according to the figures Ja, Jb, the work done by the pump 21 raises the temperature of the organic working fluid, and at a given temperature difference between the brine and the organic liquid, the exit temperature of the brine is higher, so that that of the Brine heat transferred to the working fluid

70 98 4 2/0914 · /.

is wrestling. It can be seen that the temperature between points A and H in Figures 4b and 5b is considerable is less than the temperature in the difference between points A and H of Fig. 3b. This is partly that Result of the undesired increase in temperature along the path AB in Fig. 3b and partly the result of the need to To reduce the risk of the constriction effect occurring. In the device according to Fig. 2, the pump lifting work is recovered to the enthalpy over the entire vertical Increase the length of the heat exchanger. In this way, a larger amount of heat is advantageously from the Brine removed, so that there is a higher efficiency.

The above in connection with Figures 3a and 3b mentioned constriction effect results from the fact that the heat capacity dQ / dT of the brine over the entire Temperature range of the heat exchanger 15 of FIG. 1 is almost constant, while the heat capacity of the organic Working fluid along the path of constant pressure of the Rankine cycle according to FIG. 3a at high temperatures is considerably larger than at lower temperatures. This difference in heat capacities caused by the pronounced curve shapes according to Fig. 3t »is shown, can in the constant pressure organic heat supply process of the Rankine cycle cannot be changed significantly.

Figures 4a to 5b show the effect of a further improvement the embodiment according to FIG. 2, this improvement resulting from the change in the shape of the heat capacity curve of the organic material in such a way that this as a result, has a negative thermal coefficient or calorific value. This is achieved by using heat along a selected path with changing pressure is added, which is due to the vertical heat exchange in the gravity pressure gradient cycle. The nature of the diagrams is changed by being systematic the distribution of the heat exchanger area from the ground to the

709842/0914 ' ^{/ m}

upper end of the heat exchanger element is changed.

Thus, the organic working fluid can be forced to to pass through several successive pressure zones at temperatures chosen at random can. A heat capacity curve with a thermal coefficient or calorific value of 0 eliminates the possibility of one Constriction effect, as can be seen from Fig. 4b. On the other hand, this enables low temperature differences between the temperatures of the brine and the organic liquid at the ends 146, 147 of the heat exchanger, being at the same time a large mean effective temperature difference in the desired manner along the heat exchanger results. On the other hand, a smaller heat exchanger surface is required, so that Savings in initial manufacturing costs can be made possible. Another change to the system for generating a negative thermal coefficient or calorific value the temperature profile of Fig. 5b, which is even more against the Constriction effect and against other problems of known devices is protected.

Correspondingly, there is a further improvement of the device according to FIG. 2 by modifying the effective heat transfer achieved through the wall of the tube 12; 5 between the lines 124 and 126. According to one embodiment, this is thereby achieved achieved that the heat exchanger elements are installed as shown in Figures 6 to 11, the figures 6 to 9 show particularly representative cross-sectional views successive heights along the pipe 12} in Fig. demonstrate. The pipe 123 begins at the junction with the pump turbine engine section 170, for example, as a simple heat exchanger tube with no added elements. At an arbitrary one Distance above pump section 170 are first and second tapered vertical fins or wings on one or both surfaces of tube 123 are added. For example are opposing tapered fins in FIG

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■ ¥ -

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or wings 90 attached to the outer surface of tube 123. In the illustration according to Flg. 9 are the tapered ones Portions of the wings or fins 90 are shown at their end and these wings or fins extend to the top of the well, like this in sequence is shown in Figures 8, 7 and 6. Fig. 10 shows the Way one of the fins or wings 90 tapers. the inner wings or fins 91 interacting therewith, if present, be tapered in the same way and extend to the top of the well. The sentences of wings or fins 92, 93 to Flg. 9 just got in started near the vertical elevation of this figure, so that the cross-section of its tapered smaller parts is shown is.

At the next higher altitude in the well according to FIG. 8, the fins or wings 92, 93 are now at the full Increased in size, the tapering is complete and they then extend to the top of the well. Additional tapered and opposing pairs of wings or fins 94, 95 appear in FIG. 8, with the reduced Cross-sectional size indicates that its width increases even further at the elevation of this figure. Fig. 7 shows the beginning of yet more additional tapered portions of wings or fins 96, 98 and any wings or fins are attached to the pipe I23 in a heat exchange relationship and extend to the head of the well like this Fig. 6 can be seen. It is readily understandable that many additional wings or fins or other are added tapered heat exchangers can be used and they can be of any of the shapes which is well known in the art of heat exchangers. The elimination of constriction effect disorders can take place under Can be achieved using known shapes of thermal conductors, such as the part-circular cylinder 90a shown in Fig. 11, through which the thermal conductivity between the

709842/0914

menden organic liquid of line 124 and after overhead brine of conduit 126 is readily predetermined at any vertical elevation in the well as can be easily recognized by those skilled in the art. It can easily be seen in Figures 6 to 9 and 11 that that the tubes 125 and 127 are omitted for reasons of simplicity became.

It will be seen that the arrangements of Figures 6-11 can be designed to be uniform increasing heat transfer from the pump located at the lower end of the well to the station on the surface of the earth 131 if so desired. If on the other hand successive tapers do not overlap, incremental changes can be used to make the desired To make an impact. In the further exemplary embodiment according to FIGS. 12 and 13, a different arrangement is used, to achieve incremental changes in the rate of heat transfer.

From Fig. 12 it can be seen that individual series-connected heat transfer units of the usual multi-tube type are used, such as 250, 257, 260, 262, 266 and others. The rising brine column rises again in the direction of the earth's surface I31 in the line 126 * uf, which is formed in the well lining 125 and the brine then flows out through the pipe 132. The cooled working fluid is introduced into the system at the earth's surface 131 via tube 118 and flows down from that tube through the succession of individual heat exchanger units 250, 257 , 260, 262, 266 and away from the latter. As a result, the multiplicity of individual heat exchanger units takes the place of the single heat exchanger tube 123 according to FIG. After the working fluid has driven the motor in section 170 on the pump located at the lower end of the well, it rises again to the surface of the earth in line 122

709842 / 09U

of the thermally insulated pipe 121.

The rate of heat exchange from the rising brine to the downward flowing working fluid is determined by the lower to the upper end of the arrangement of FIG. 12 progressively enlarged, for example by progressively the number of heat exchanger tubes in each successive heat exchanger unit is increased, so that the heat transfer is increased, as described above. Merely as an example, the Heat exchanger unit 266, which is fragmentarily attached to the lower At the end of FIG. 12 is shown, only two heat exchanger tubes 267 and the liquid flows in these tubes from the annular elbow or distribution head 265 which is described in more detail with reference to FIG.

The heat exchanger unit 262, which feeds the distribution head 265 from a distribution head 261, has a larger one Number of heat exchanger tubes 26}, as the unit 266, so that the heat exchanger unit 262 has an increased heat transfer characteristic and three such tubes 26j5 can be seen in FIG. The next heat exchange before purity 26O, which is shown fragmentarily, feeds the distribution head 261 and has a further increased number of heat exchanger tubes 259. Hence convicted this heat exchange unit 260 has a larger amount of heat than the unit 262. The number of tubes and the total Heat exchange area in each heat exchanger unit increases progressively towards the top of the well and the final heat exchanger unit 250 feeds a distribution head 256 from the input distribution head 249 and has the largest heat transfer surface because it is the largest Has number of heat exchanger tubes 25I. The distribution head 256 feeds the heat exchanger unit 257, which is a smaller one Heat transfer characteristic as the unit 250 having. There are nine tubes in the heat exchanger unit 250 can be seen, while the unit 257 has five tubes.

./. 709842 / 09U

It is apparent to those skilled in the art that the arrangements of heat exchanger tubes in concentric circles or in regular radial V / iron can be formed and that the sizes and dimensions of the individual heat exchanger tubes are variable can be made as long as the desired progressive increase in heat exchange is achieved.

An example of a distribution head or elbow such as distribution head 256 and its inlet and outlet heat exchanger tubes is shown in Fig. I3. The distribution head 256, which has an array of inlet pipes 25I, which form the heat exchanger unit 250 is used for supply the working fluid flowing downwards into the next lower one Heat exchange unit 257 consisting of the tubes 258. The distribution head 256 surrounds the thermally isolated Tube 121 and is disposed in the well lining 125 (not shown). The insulated tube 121 gives the Inner conduit 122 and it may be lined with insulating material (not shown). A common sliding connection an interface 277 is formed between the upper and lower parts of the tube 121, this interface 277 can be provided with a conventional sealing mechanism.

The distribution head 256 consists of separate parts which are connected to one another at the annular pipe thread connection point 2Jk. The lower part of the distribution head 256 includes a head piece 272 provided with openings for receiving the heat exchanger tubes 258 of the heat exchanger unit 257. The head piece 272 is connected to the pipe 121 in a sealed manner. The lower part also saw a threaded cylindrical shell 275. In the same way, the upper part of the distribution head 256 includes a head piece 27I provided with openings, which is connected to the tube 121 and receives the heat exchanger tubes 251 of the heat exchanger unit 250. The top of the distribution head 256 also includes a threaded one

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cylindrical shell 272, its thread with the thread the cup 275 matches. This is how the working fluid flows of the large number of tubes 251 in the Heat exchanger unit 250 in the relatively smaller number of tubes 258 of the heat exchanger unit 257. The elimination of the Constriction effect disorders also result in this Case, however, here by using the series of discrete heat exchanger units 250, 257, 26θ, 262, 266, the result in a gradually increasing heat transfer from the bottom to the top of the arrangement.

A preferred embodiment of the thermodynamically driven one Turbine engine of the turbine engine section 170 of Fig. is shown in detail in Figures 14-18. It is readily apparent that the turbine engine is a general Has a shape similar to that of the Mctor described in the German Offenlegungsschrift No. 2,5350,635 mentioned above is, although this engine has been modified to allow it to operate in the organic cycle of the present invention Adapt device. In particular, this motor is modified so that it has a large volume flow of an organic Absorbs working fluid that is in the supercritical state remains and this same fluid is used to lubricate the radial and thrust bearings while in the engine according to the aforementioned German Offenlegungsschrift the water introduced from the surface is used for this purpose. The in Figures 14 and The storage system shown is further modified in detail, that an escape of the expensive organic liquid in the geothermal brine solution is prevented.

It can be seen from Figure 14 that the concentric conduits 122, 124 and 126 co-exist in the liquid turbine hub 170 extend. The one in a supercritical state heated liquid in line 124 flows In an array of injectors indicated at 151, the

709842 / 09U

have a generally customary structure. The nozzles 151 are shown in more detail in the development according to Fig. I7 and they are used in the usual V / else to a large volume flow of liquid in supercritical State against the flapper 152 of the turbine engine. An annular holder 153 holding the assembly of wings 152 carries is in the usual manner on a wheel rim 155 attached, the latter being part of a wheel with a set of spokes 156 and a hub I6I is. the When the rotor system rotates, the hub 161 causes the shaft point I60, 164 and 194 to rotate, the hub I6I being fixed to the Shaft part I60 through a washer I59 and a nut 158 is attached, which is screwed onto a thread extension 157 of the shaft part I60.

The turbine engine system has an arrangement for deflection the organic ones that are still in the supercritical state Working fluid upwardly into the insulated inner or outlet line 122. To this end, a turbine body block I90 has an annular uniformly curved torcid-shaped channel I63, which is led by the rotating blades 152 leads in the radial direction inward onto the shaft part I60 and at the same time the direction of the liquid flow so changes that the liquid flows upwards when it leaves the channel I6j5. The toroidal channel 163 is through a suitably curved surface I65 formed in the block 190 and through the surface of the opposite one Annular ring or the guide 162 is formed. The guide 162 can be arranged in a radial direction extending wings I80 be supported, which in addition to holding the guide 162 continues in the sense a deflection of the outflowing liquid act, so that the velocity vector of this liquid generally becomes vertical. Accordingly, it can be seen that a toroidal expansion channel having uniform sides

709842 / 09U

for the supercritical fluid is formed, which the expanding fluid, as it leaves the array of vanes 152, carries through the spokes 156 of the turbine motorcycle passes through. The flowing through of the organic working fluid through the spokes 156 is facilitated in the manner illustrated in FIGS Figures 15 and 16 is shown and as described in the above-mentioned German Offenlegungsschrift. the Spokes 156 are individually inclined relative to the direction of rotation of the ring 155, so that their effect in the selected The speed of rotation is essentially neutral and the angle of incidence of the spokes I56 with respect to the direction of flow of the working fluid is in turn such that it corresponds to the fluid flow neither supply nor derive energy from this when this liquid flow in the line 122 after above flows. This way, the need for an additional upward-facing one becomes consuming a lot of space Line outside of the hydrodynamic turbine engine avoided.

Figures 14 and 18 show the liquid storage system for supporting the shaft part 160 and the liquid turbine engine in block 190. This bearing system includes an upper radial bearing (Fig. 14) and a thrust bearing (Fig. 18) and a lower radial bearing. The upper radial bearing according to FIG. 14 can have a conventional structure or it can be a bearing which is essentially the same as the tilting chuck arrangement of the above-mentioned German Offenlegungsschrift is, both the shaft part I89 is surrounded by a hollow cylinder 191 made of aluminum oxide, which is attached to the shaft part I89 is attached. In the usual case, three act independently Tilt chuck bearing surfaces coincide with the bearing surface of the I9I alumina cylinder and a typical one Construction uses a fastener with a chuck alignment shaft 203 inserted in a bore I97 is located in block I90. The chuck adjustment shaft 203 is set according to the setting of the radial one te11-

7 0 9842/09 U ^{# /} -

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ble threaded part 198 is set and the shaft 203 ends in a hardened steel ball 196 which is partially received in a counterbore. The ball 196 protrudes into the interior of the block 190 and presses against a matching recess in a bearing holder block 193. A sleeve 192 made of aluminum oxide is attached to the inner surface of the bearing holder block 193. The sleeve 192 and the cylinder 19I have adjacent bearing surfaces, between which the organic working fluid is present as a thin lubricating film, as will be described below. In practice, three identical tilting chuck bearings are used in the radial bearing in order to completely determine the actual position of the shaft part I89. It can be seen that the lower radial bearing system of Fig. 18, which uses the shaft bearing part 215, aluminum cylinder 216, aluminum sleeves 217, bearing block supports 218 and balls 221, and tilt chuck alignment shafts such as 222, in the same manner as the radial bearing can be constructed according to Fig. Ik .

Between the two radial bearing units with the shaft parts 189 and 215 are connected is a thrust bearing system arranged, which is shown in phantom in Fig. 18 and which may generally have the shape as in the above German Offenlegungsschrift 2,530,635 mentioned above is. For example, the tilt chuck thrust bearing system includes an enlarged and tapered portion 210, to form a horizontal boundary layer element 211. the The lower or pressure surface of the element 211 can be formed by a planar ceramic ring 209. The ring 209 represents schematically, for example, the tilting chuck thrust bearing system according to the above-mentioned German patent application and has a plurality of ceramic bearing surfaces that cooperate with the lower or bearing surface of element 211. The bearing surface of the element 211 and the horizontal bearing surfaces of the tilting chucks cooperate,

709842/0914

to determine the vertical position of the shaft parts 19 ¹ J, 214, 215, as is described in the aforementioned German patent application.

In order to enable the additional use of the organic working fluid to lubricate the bearing system, a Feed system used. This feed system also ensures that no part of the expensive organic working liquid from the pump system goes into the hot ascending brine solution is lost and that this brine does not enter the camp. As can be seen in FIG. 14, there is a removal key 179 with the toroidal expansion channel I6j5 in connection and carries organic working fluid (after passing through impingement vanes 152) into a manifold 182, the is formed by a tube 18l. The liquid flows down through the pipe 18l and arrives in the radially arranged Channels 2 ^ 0 in block 190 (Fig. 18). The organic liquid passes through the channels 220 into a cavity 220, the surrounds the lower radial bearing on the shaft part 215. At this point, the interfaces between the aluminum oxide cylinder 216 and the bearing liners 217 with the organic Liquid soaked and lubricated while the liquid flows up through a channel 213 into the thrust bearing, that by the interacting elements 209, 210 and 211 is formed. While the liquid through the channels 213, 212, 200 flows, it lubricates the matching thrust bearing surfaces in the same way.

The organic working fluid then flows through to the top the annular channel 200 around the shaft portion 194 in Fig. 14 and it exits into the cavity 199, the upper Radial bearing on the shaft part I89 surrounds so that the adjacent surfaces of the bearing members 191, 192 are lubricated. Eventually the liquid is passed through a simple screw pump I83 pumped close to the top through an annular channel 164 and flows out into the expanded or relaxed organic liquid that flows through

709842 / 09U ./.

line 122 passed up to earth's surface I3I will. In this way, the various bearings are lubricated so that reliable long-term operation is possible.

A leak of the expensive organic labor and entry of the corrosive brine well water into the interior of the block 190 is indicated by the in Fig. 18 below the Prevents radial bearing on the shaft part 215 shown end face diaxing. The lower end face 219 of the enlarged shaft part 215 lies against the upper end face a ring 230 having a bore, which is provided with an O-ring 231, which is connected to the cylindrical surface of the shaft portion 182 is in contact. The ring 231 is endeavors to rotate with the shaft portion 182. The ring 251 forms a conventional pressure balanced seal with the upper surface 232 of a stationary portion 233 of the seal. The flowing of the organic liquid downwards is further prevented by an O-ring 234, the In A groove is arranged in the block 190 and is connected to the outer cylindrical surface of the stationary seal point 233 is engaged. A coil spring 236 lies with its lower end to an abutment 237 in the block 190, while the upper end of this spring with the underside 235 of the stationary seal part 233 in engagement stands. Therefore, the elements 230 and 233 are held together and their orenc surface 232 is also through the organic working fluid lubricated. Alternatively can a bellows hermetically sealed from surfaces 235 and 237 can be used in place of spring 236. In this latter construction, the O-ring 234 can be omitted.

It can be seen that the embodiment described a geothermal energy harvesting device with improved efficiency, which the thermal energy

709842 / 09U

takes advantage of the well water stored in hot solvent when it goes up to the surface of the earth an elongated linear heat exchanger element is pumped is to continuously heat a downward flowing organic liquid in a supercritical state. The increased energy of the organic liquid goes deep down Used in the well to operate a thermodynamic turbine-driven pump to the hot, solvent leading well water at high pressure and always in a liquid state to the surface of the earth, from where the water is pumped reintroduced into the earth. The temperature difference between the upward flowing brine and the downward flowing flowing organic liquid is controlled in a predetermined manner along the underground elongated heat exchanger element. After driving the at the bottom of the well arranged turbine-driven pump, the organic liquid rises in a thermally insulated pipe to the earth's surface and on the earth's surface become electrical Power generating devices are driven by the organic liquid duct, whereupon these are returned to the well so that it is reheated as it passes through the elongated heat exchanger.

The arranged in the well part of the device of the geothermal system is significantly simplified compared to known devices, because it is not necessary to have a Well arranged pressure regulator and a steam generator to use and because the rising hot brine directly when ascending in the well is used in a more effective way to dissipate the heat in an elongated manner exchange rectilinear heat exchange arrangement, so that the introduction of heat into the binary liquid at constant temperature is avoided. The device yields an ideally small and essentially constant temperature difference between the rising brine

709842/0914

and the downward flowing organic working fluid along the entire length of the elongated heat exchanger. Therefore, a pipe that in known devices easily meets was used as a conduit, a twofold task and it now serves at the same time as an elongated one more effectively Heat exchanger. The pump arranged at the lower end of the well only has to handle the low friction losses in the brine pipe and overcome the electrical power at the surface of the earth for a given brine source temperature and brine flow rate generated is considerably increased. The adapted thermal properties the brine solution and the selected organic working fluid interacting with it are such that enables an extremely effective thermal energy exchange will. Furthermore, the equipment costs and the operating costs as well as the complexity of the surface arranged facilities significantly reduced because essential elements of the known devices are no longer required will.

70 9 842 / 09U

Claims (7)

Patent claims: A method of transferring thermal energy from "~" an inner hot area within the earth for use in the vicinity of the earth's surface, characterized by the steps of transferring a first initially relatively cool liquid from a first station in the vicinity the earth's surface (131) to a second station in the earth, the use of thermal energy to convert the first liquid into a supercritical state during the transfer from the first to the second station, the use of the first liquid in the supercritical state to drive pump devices ( 172) at the second station, the use of the pump means (172) for pumping a second liquid from the inner hot area (84) to the first station at a pressure at which the second liquid is always kept in a liquid state, the transfer of the im first liquid in the supercritical state after the drive d he pump means (172) in a thermally isolated relationship with respect to the second liquid up to the first station and the removal of the thermal energy from the first liquid in a supercritical state at the first station in order to achieve useful power. 2. The method according to claim 1, characterized in that it rejects, that the step of using the pump means (172) to pump the second liquid from the inner hot area (84) to the first station the direct return of the second liquid into the earth at the Earth's surface (131) includes. 7 0 ·:? U? / 0 9 1 4 / ORIGINAL INSPECTED 3. The method according to claim 2, characterized by the additional step of reverse conversion of the first liquid in the relatively cool first liquid after removal of the thermal Energy. H. A method according to claim 2, characterized gekennze et ichn that steps relating to the first liquid in a closed circuit according to the pressure-enthalpy diagram out according to FIG. Ha or 5a of the drawings. 5. The method according to claim 2, characterized in that the step of using the thermal energy to convert the first liquid to the supercritical state includes the additional step of using the second liquid after pumping to transfer heat to the first liquid in vertically extending heat exchanger devices ( 123) according to a temperature / vertical distance diagram according to FIG. 4b or 5b of the drawings. 6. Device for performing the method according to one of the preceding claims for transferring thermal Energy from a hot area in the interior of the earth to utility facilities near the earth's surface, ge denotes t through heat exchanger devices (123), which essentially extend from a first station adjacent to the earth's surface (I3I) to a second station extend in the interior of the earth, and the one initially located in a relatively cool state first liquid of the first station to the second station while they transfer the first liquid into the supercritical state convert to drive devices (I70) at the second Drive station from the drive devices (I70) pumping devices driven at the second station 70 2 342 / 09U -X- (172) for pumping a second liquid from the hot area (84) in the earth's interior under a pressure at which the second liquid is always kept in a liquid state, conduit parts (126) which are in heat exchange relationship with the heat exchanger devices (125) and the second liquid from the pump devices (172) transfer first station, thermally insulating line parts (127) for transferring the in supercritical state located first liquid from the drive means (170) to the first station under thermal Isolation from the second liquid, and thermal energy transfer devices (101) on the first Station for extracting part of the thermal energy from the first in a supercritical state Liquid for generating useful power. 7. Apparatus according to claim 6, characterized by with the output of the thermal energy transfer devices (101) coupled devices (I09) for supplying the first liquid in a relatively cool state to the heat exchanger devices (123) at the first station. 8. Apparatus according to claim 7, characterized by liquid transfer devices (132, 133) at the first station, which are connected to the line parts (126) at this station, for the second liquid direct back into the earth. 9. Apparatus according to claim 8, characterized in that the insulating line parts (127) are arranged within the heat exchanger devices (123) and that the heat exchanger devices (123) are arranged in heat exchange relationship within the line parts (126) . 7 0 9 842/09 U ^{m /} ' 10. Apparatus according to claim 6, characterized in that that the heat exchanger devices (23) and the Line parts (126) are arranged so that the flow direction of the first liquid in the heat exchanger devices (123) always runs opposite to the direction of flow of the second liquid, so that the temperature the second liquid as it passes through the line parts (126) from the second station to the first station is continuously reduced. 11. The device according to claim 6, characterized in that that the heat exchanger devices (123), the line parts (126) the insulating line parts (127) and the drive devices (170) are arranged so as to cooperate are that a pressure gradient between the first liquid in the heat exchanger devices (123) and the first liquid in the insulating line parts (127) is maintained in order to drive the drive devices (170) and in this way to generate thermal energy from the second liquid to the thermal energy transfer devices (101) to be transferred. 12. The device according to claim 7, characterized in that the heat exchanger devices (123), the drive devices (170), the insulating line parts (127), the devices (109) for supplying the first liquid to the heat exchanger devices (123) and the energy transfer devices ( 101) are arranged in a closed circuit, so that the operation takes place according to the pressure-enthalpy diagram according to Fig. 4a or 5a of the drawings. 13. The device according to Anqpuch 6, characterized in that the first and second liquids have substantially constant specific heat properties as a function of temperature. 909842/0914 / 14. Apparatus according to claim 10, characterized in that the heat exchanger devices (125) and the line parts (126) so arranged during operation are that a substantially constant temperature difference between the oppositely flowing first and second fluids is maintained along the entire travel path. 15. The device according to claim 10, characterized in that the heat exchanger devices (123) and the line parts (126) so arranged during operation are that a greater temperature difference between the oppositely flowing first and second Liquids along substantially the entire travel distance compared to the temperature difference at the opposite ends of the heat exchange means (123). 16. The device according to claim 6, characterized by means of the thermal transmission properties of the exchange devices (123) from a lowest value adjacent to the second station Increase to a maximum value adjacent to the first station. 17. Device for performing the method according to one of claims 1 to 5 for the transfer of thermal Energy from a geothermal liquid from a hot area in the earth's interior for use at the earth's surface, marked by thermally insulating pipe parts (127), the first Conduit parts (122) form thermally conductive pipe parts (123) which surround the thermally insulating pipe parts (127) are arranged around to form second conduit parts (124), third pipe parts (125), which are essentially coaxially around the thermally conductive pipe parts (123) 709842 / 09U / -Jf- are arranged to form third line parts (126), pump devices (172) for pumping the geothermal Liquid towards the earth's surface through the third conduit portions (126) in heat exchange relationship with the thermally conductive pipe parts (12j5), and drive devices (170) for driving the pump devices (172), wherein the drive devices (170) are operatively connected to the second conduit parts (124) and the flow of a working fluid in a supercritical state in the second line parts Address (124) from the surface of the earth (l ^ l). 18. Apparatus according to claim 17, characterized by means of supplying the working fluid in the supercritical state the exit from the drive devices (170) into the first line parts (122) for return to the earth's surface 19 · Device according to claim l8, characterized by thermal energy transfer devices (101), which are connected to the first line parts (122) on the earth's surface (131) to absorb part of the thermal energy derive from the working fluid in the supercritical state to gain useful power. 20. The device according to claim 19, characterized by devices coupled to the output (I05) of the thermal energy transfer devices (101) (109) for supplying the working fluid in a relatively cool state to the third line parts (124). 21. The device according to claim 20, characterized by fourth line parts (1J52, 135) with the third Line parts (126) are connected at the first station 7 0 3842/09 U · / · Earth to- and return the geothermal fluid directly to the. 709842 / 09U